Combat Medic eFAST with Novel and Conventional Portable Ultrasound Devices: A Prospective, Randomized, Crossover Trial.

Abstract

Background: Extended Focused Assessment with Ultrasonography in Trauma (eFAST) reliably identifies noncompressible torso hemorrhage (NCTH), a major cause of battlefield death. Increased portability of ultrasound enables eFAST far forward on the battlefield, and published data demonstrate combat medics can learn and reliably perform ultrasound exams. One medical company developed an ultrasound device with an intuitive graphical user interface (GUI) and novel, finger-worn transducer with built-in linear and phased arrays, referred to as the novel device. We evaluated combat medic eFAST performance between the novel and conventional device.

Methods: This was a prospective, randomized, crossover trial completed at a single US military installation. Subjects were US Army combat medics with no previous ultrasound experience. Subjects performed an eFAST on a live human and a simulation model with both devices after a brief training intervention. Our primary outcome was time in seconds for eFAST completion, limited to 600 seconds. Secondary outcomes included diagnostic accuracy, technical adequacy using a validated task-specific checklist, and end-user appraisal of device ease-of-use with 5-point Likert items. This study was approved by the local institutional review board.

Results: Forty subjects volunteered, most were male (67.5%), less than 36 years old (95.0%), and grade E-4 or below (75.0%). Subjects performed a total of 160 eFAST scans (80 novel, 80 conventional). We found no significant difference in time for eFAST completion between the novel and conventional devices (391 seconds [95% CI 364, 417] versus 352 seconds [95% CI 325, 379]; p = 0.71). We also found no significant differences between the novel and conventional devices with respect to diagnostic accuracy (91.5% versus 89.2%; p = 0.28) and technical adequacy (75.0% versus 72.5%; p = 0.28). However, we did find that subjects favored the image quality of the novel device (4.3 versus 3.6; p is less than 0.01), while favoring the conventional transducer (3.8 versus 4.3; p = 0.04).

Conclusion: Combat medic eFAST performance utilizing both devices did not differ with respect to time to completion, diagnostic accuracy, and technical adequacy. Medics with limited ultrasound experience performed diagnostically accurate eFAST after a brief training intervention. Future research should assess learning gaps and skill retention in order to guide development of US military ultrasound training programs for combat medics.